[单选题]
A nuclear reaction is said to be38cm0ec e,l)ebdwc9z exothq x2q8+l vw 6kcdauy0ar fl )w9qq88as;.+p pjermic if the total kinetic energy is
A. less after the reaction than before.
B. equal both before and after the reaction.
C. greater after the reaction than before.
D. zero after the reaction.